1) Field of the Invention
The present invention relates to a method of and an apparatus for performing a special effect processing to an image.
2) Description of the Related Art
Various techniques for processing color images have been proposed. For example, image processing techniques such as lightness adjustment, contrast adjustment or hue correction are known. To process an image is also referred to as “to apply a special effect processing”.
As one of such special effect processing, there is a processing for designating a specific color among full colors of a full-color image, printing only the specific color and printing the other colors as a monochrome image (which processing will be referred to as “designated color printing”). The designated color printing highlights the portion(s) with the specific color and so has a relatively wide range of utilization. For example, the designated color printing is used to highlight a color of a lipstick in an advertisement, such as on a poster to make an impact on the viewer of the poster. The lips of a woman model in the poster are printed in color and the rest of the poster is printed in monochrome.
Conventionally, the special effect processing is performed on a computer using dedicated software and the processed image is printed with a color printer. For example, Photoshop (trademark) manufactured by Adobe System Corporation may be used to perform the special effect processing. Photoshop has various other special effect functions in addition to the designated color printing explained above.
However, the softwares that are dedicated for the special effect processing are relatively expensive and difficult to operate. Therefore, there is a drawback that the dedicated software requires a skilled operator.
Further, there is known a two-color separation plate which can designate two-color separation on a printer driver and which separate two colors using an arbitrary ordinary application software (see, for example, Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2001-197324).
According to the two-color separation plate, however, if specific color printing for printing only colors of a monochrome-base image in colors is performed, the apparatus can deal with up to two colors, i.e., black+one color. To express a second color such as red or blue, it is disadvantageously necessary to separately prepare a red or blue specific ink. Besides, whenever one specific color to be used has to be changed, it is disadvantageously necessary to change the ink.